1. Field of the Invention
This invention relates to mechanically fixing an electrical connector to substrates, such as printed circuit board, or in particular to devices commonly known as boardlocks.
2. Description of the Prior Art
Printed circuit boards that are loaded with associated electronic components are widely used throughout the electronic industry. In order to interface with these boards, electrical connectors are also attached to the boards with their contacts being connected with circuit traces thereupon. In order to mechanically fix these connectors to the printed circuit boards, it is known to use a device commonly called a boardlock. Typically, the boardlock provides an mechanical anchor to the board such that the connector is held in place and any forces exerted as a result of mating or de-mating can be isolated in the connector housing as opposed to being transferred to the electrical interface between contact and circuit trace.
One conventional form of boardlock extends through a hole in the printed circuit board where it is deformed on the opposite side in a manner that prevents withdraw from the hole. Other boardlocks utilize retention arms that engage the inside surface of the hole such that it is not possible to pull the connector free of the board. Boardlocks have found common use in electrical connectors that utilize contacts having both pins for engaging through-hole on the circuit traces or surface mount feet for being soldered directly to a traces. A problem with the known boardlocks exists when the size of the printed circuit board becomes small. In these instances, the thickness is generally reduced thereby making it difficult for barbs to engage along the inner surface of the hole. In high density applications, typically both sides of the printed circuit board will be used which presents a further problem of either getting the tooling in the proper area to deform the boardlock or that the boardlock extending through the board is taking valuable board area. An example of one of these high density boards is 1.6 mm thick having a 2 mm diameter mounting holes where the size of the holes could have a tolerance .+-.0.127 mm. Additionally, in these high density applications where small connectors that are surface mounted are used, it is desirable that the boardlock also performs the function of holding the connector in place while the board is being processed prior to soldering of the contacts to the circuit traces. The processing sometimes includes inverting the board.
Finally, it is an additional problem that the mechanical strength of the material used for the boardlock in such a small application is usually low. The boardlock, if not properly inserted, could be deformed and destroyed thereby disrupting the manufacturing process.